Scope of work
Pacific Marine Group carried out works along the river section of Oilsearch’s export pipeline to replace old CP Stations and river marker signage in the Kikori and Nakari Rivers, located in the Gulf Provence of PNG. The pipeline is used to transfer oil and gas form OSL’s Central Highlands processing plants, down to the coast and out into the Gulf of Papua to their offshore loading facility “Kumul Platform”.
The PMG181 & PMG182, both 54m x 18m flat top barges, were mobilised to site from Townsville in February to complete site works ahead of and through PNG’s wet season.
CP Station Works: The works involved the demolition of the existing land based cathodic protection / test point station structures/helipads, which had passed their design life. The old stations were replaced with 3 new structures, mounted atop monopiles driven into the riverbed, with the new CP equipment powered by solar panels and battery banks. The demolition works included removal of the old existing structures, along with sheet pile which, following removal was loaded onto barges and transported to Port Moresby for recycling. In addition, a new anode Ground Bed (20 anodes) was installed on land adjacent to Impressed Current Station 2 (IC2), to ensure the pipeline will be protection well into the future.
The works included the removal of around 30 existing river markers which consisted predominantly of signs mounted atop steel pipe driven into the riverbed or floating buoys that had been installed to replace signs that collapsed over the years since originally installed in 1992.
PMG mobilized two tug and Barge Combinations from Townsville to Kopi, where all materials were located, to enable works to be carried out on two separate work fronts throughout the works.Each construction barge was equipped with a full array of construction plant and equipment including:
• Crawler crane (250T or 180T)
• Hydraulic Pile Guide
• Pile Storage Frames
• Vibratory Hammer
• Site Office
• Storage containers
• 4 Point Anchor System
• Pair of Mooring Spuds
• Hydraulic Power packs/ winches
A 20T excavator was also mobilized to undertake the installation of the new anode ground bed at IC2 and was later used, with a grab attachment, for the bundling of demolished steel prior to backloading from Kopi to Port Moresby.
With both barges having a full spread of construction equipment crews were able to operate independently of each other to minimize the site works duration.
PMG had around 27 crew on site at any one time, with crews staggered by 2 weeks to maintain continuity of works on site.